Field of the Invention and Description of the Prior Art
This invention relates to an improved mechanism for operating a slat shade assembly of the type that is located between a pair of glazing panels of a window construction.
There are known window constructions which utilize a slat shade or "blind" as part of the window construction itself. One such construction (sold under the trademark SLIMSHADE) comprises a blind assembly having thin, narrow slats mounted on a cord ladder. The blind or slat assembly is positioned between two glass panels, one being an exterplor glass or glazing panel and the other being an interior glass or glazing panel so as to thereby form an insulated, double glazed window. It has been conventional, in such a construction, to provide an operating dial for adjusting the blind assembly between its various positions, such as for privacy and for sun control, such as, in the summer to prevent undue heat load and, in the winter, to permit sunlight to add heat to a room. These slat shade--double glazing panel window constructions are available for use in various types of window constructions, including double hung and casement windows. In addition, screens may be mounted on the interior side of the window frame and the slat shade is still operated.
Although the known mechanisms for operating the known slat shades have been of generally satisfactory construction, these known operating mechanisms have required routing of the wood sash and the operating mechanism can be installed in the routed-out space in the window sash and then covered by an escutcheon. Again, although, in the original manufacture of the assembly, this can be accomplished, such an assembly was difficult to accomplish in a field installation.
Also, in the known operating mechanisms for the slat shades, a direct drive was provided, which only allowed for approximately 90 degrees of movement of the slats between the extreme positions. The direct drive also limited the ability of the drive mechanism to resist the spring force generated by the cord ladder system carrying the slats and it would often be difficult to maintain the slats in the desired position. The operators also generally utilized a thumb wheel which was somewhat difficult to operate and often became painted and was difficult to move after painting to thereby destroy the advantage of the assembly itself. Because of these disadvantages of the known operators for the slat shade it would clearly be highly desirable to provide an improved operating mechanism for a slat shade assembly of the type which is located between the glazing panels of a window construction.
One known prior art system using a magnetic drive system is shown in U.S. Pat. No. 3,722,572. However, the lack of a positive drive connection is considered a significant disadvantage.